Binorum Plössl 40mm 45° 1,25″ Eyepiece

Eyepiece Binorum Plössl 40mm 1,25" - Universal Eyepiece for Every Telescope

Plössl eyepieces are among the most popular and versatile optics for astronomical observations. This classic 40mm Plössl is compatible with any telescope equipped with a standard 1.25" barrel – simply insert it and start exploring the night sky.

Crystal-Clear Images

Thanks to multiple anti-reflection coatings on all optical surfaces, you'll get sharp, bright, and vivid images without distracting reflections. Quality optics eliminate aberrations and provide faithful rendering that both beginners and experienced observers will appreciate.

Made for Deep Space

With its 40mm focal length, this eyepiece is the ideal choice for observing deep-sky objects. The wide field of view creates an impression of infinite space during night observations – the contrast between the edge of the field and the star background is so minimal that you barely notice the boundaries.

Perfect for observing:

• Extensive star clusters and stellar fields
• Large nebulae in their full glory
• Galaxies with broader surrounding context
• The Milky Way and panoramic views of the night sky

Proven Design, Reliable Performance

Plössl eyepieces have earned the trust of astronomers worldwide thanks to their simplicity, reliability, and excellent price-to-performance ratio. The four-element optical construction ensures quality imaging at an affordable price.

Key Features

Focal Length: 40mm – low magnification for wide views
Barrel Diameter: 1.25" (31.7mm) – universal standard
Anti-Reflection Coating: Multiple layers on all surfaces
Best For: Deep-sky objects, star clusters, nebulae, panoramic views
Compatibility: All telescopes with 1.25" output

The Perfect Addition to Your Equipment

Every astronomer needs a quality long focal length eyepiece for finding objects and wide-angle views. The Plössl 40mm is a reliable choice that will serve you for years and become an essential part of your observing kit.

Discover the beauty of deep space with an eyepiece you can count on.

Specifications

Type of eyepiece: Plössl

Focal length: 40 mm

Connection type: 1.25″

Variety of eyepiece: Planetary

Apparent field of view: 45°

Eye relief: 31 mm

Number of optical components / single lenses: 4/2

Coating of optical system: Multiple

Length: 85 mm

Telescope parameters using this eyepiece

Aperture mm

Focal length telescope mm

Specifications:

Magnification:

Telescope magnification is calculated by dividing the telescope's focal length by the eyepiece focal length. A Barlow lens also affects magnification: the power increases according to the Barlow's multiplication factor.

Field of View:

The field of view is the angular size of the sky area visible through the telescope with a given eyepiece. It depends on both the magnification and the eyepiece's apparent field of view. For comparison, the Moon's average apparent diameter is 0° 31' 5" (0.518°).

Exit Pupil:

The exit pupil is the diameter of the light beam that exits the eyepiece and enters your eye. A larger exit pupil produces a brighter image. Exit pupil is calculated by dividing the aperture diameter by the magnification.

Focal Ratio:

The focal ratio (also called f-number or f-stop) is the ratio of the telescope's focal length to its aperture diameter. Telescopes with focal ratios from f/4 to f/6 are typically called "fast" telescopes, suitable for both visual observation and astrophotography. Telescopes with focal ratios between f/6 and f/15 are better suited for visual observation than photography, and generally make it easier to achieve higher magnifications.

Resolution (Dawes Limit):

Resolution is the angular size of the smallest details and objects that can be distinguished through this telescope under excellent observing conditions. This theoretical limit assumes perfect optics and atmospheric conditions.

Limiting Magnitude:

This is the faintest star magnitude visible through this telescope under excellent observing conditions with dark, clear skies and a fully dark-adapted eye.

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This product is available in the following variants:
Binorum Plössl 3,6mm 43° 1.25″ Ultra High Power Planetary Eyepiece	39.35 €
Binorum Plössl 4mm 52° 1.25″ Eyepiece	39.35 €
Binorum Plössl 6mm 52° 1.25″ Planetary Eyepiece	39.75 €
Binorum Plössl 6,5mm 50° 1.25″ Planetary Eyepiece	40 €
Binorum Plössl 10mm 50° 1.25″ Eyepiece	40.20 €
Binorum Plössl 12,5mm 50° 1.25″ Eyepiece	40.20 €
Binorum Plössl 20mm 50° 1.25″ Eyepiece	40.20 €
Binorum Plössl 40mm 45° 1,25″ Eyepiece	41 €